visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
장소 #1323(E6-2 1st fl.) 
일시 Jun 1 (Wed) 4 PM 
연사 Kil-Byoung Chai, Caltech 

Laboratory experiments relevant to mesospheric clouds, Saturn’s rings & astrophysical jets

 

Jun 1 (Wed) 4 PM, #1323(E6-2 1st fl.)
Kil-Byoung Chai, Caltech

 

An rf discharge with liquid nitrogen cooled electrodes and injected water vapor has been used to study nucleation, growth, and dynamics of water-ice grains spontaneously formed in a plasma environment. Examples of water-ice dusty plasmas include polar mesospheric clouds, Saturn’s diffusive rings, and protoplanetary disks. We found that fast grain growth to nonspherical shape with up to 5:1 elongation occurs when the water molecule mean free path exceeds the ice grain screening length. Ice grains grow largest in light gas plasmas, up to 500 µm long in hydrogen plasma. Elongated ice grains align along the plasma ambipolar electric field. Microscope images reveal that the ice grains have fractal nature with 1.7 typical fractal dimension. After the growth process ends, poloidal vortex motion of ice grains is observed and is shown to result from the non-conservative ion drag force.

The Caltech jet experiment produces low beta, high Lundquist number, high density (~1022 m-3) MHD-driven plasma jets and so is similar to astrophysical jets and solar corona loops. We have recently studied various phenomena associated with magnetic reconnection induced by a kink-driven Rayleigh-Taylor instability using comprehensive diagnostics. The results of this study include the following: A spatially localized EUV burst is imaged at the presumed position of fast magnetic reconnection in a plasma jet; the existence of this localized EUV burst indicates strong localized electron heating. Circularly polarized high frequency whistler waves are simultaneously observed indicating that Hall dynamics likely governs the reconnection. Spectroscopic measurement shows simultaneous fast ion heating. We propose that the electron heating is consistent with Ohmic dissipation while the ion heating is consistent with ion trajectories becoming stochastic.

 

번호 일시 장소 연사 제목
168 2016/09/29-12/13  E6-2, #1323  Sangyoon Han 외  2016 Fall, Physics Seminar Serises file
167 Jun 24 (Mon) 11:00  E6-2, #1323  Dr. Henning Schomerus  Topological photonic anomalies file
166 July 25(Thur.),4:00PM  E6-2, #1323  Prof.Bohm-Jung Yang  Band topology of twisted bilayer graphene file
165 July 31(Wed.)/ 16:00  E6-2, #1323  Dr. Ivan Borzenets  Features of ballistic superconducting graphene file
164 2015/08/03,10:30AM  E6-2, #1323 (Seminar Room)  Dr. Jonghee Yoo (Fermi National Accelerator Laboratory, USA )  Axion Search
163 2015/10/23, 3PM  E6-2, #5318  Dr. Helmut Soltner (Forschungszentrum Juelich)  Development of a Rogowski Coil as a new beam position monitor
162 2015/11/06, 4:30 PM  E6-2, #5318  Dr. Youngkuk Kim (University of Pennsylvania)  Topological Dirac line nodes in centrosymmetric semimetals
161 February 12(Web.)  E6-2, #5318  Prof. Kunio Kaneta  From inflation to new weak-scale file
160 2015/07/16, 4PM  E6-2, 1318  Dr. Kyunghan Hong(MIT)  Next-generation ultrafast laser technology for nonlinear optics and strong-field physics
159 2015/07/16-07/17  E6-2, 1501  Sang-Wook Cheong (Rutgers Univ.)  KAIST Physics Distinguished Lecture
158 2016/03/11-06/09  E6-2, 1501 외  박권(KAIS) 외  Physics Seminar Serises : 2016 Spring file
157 Jul 3rd, 2019 (Wed)  E6-2, 2501  Kyung Soo Choi  Many-body quantum electrodynamis (QED) with atoms and photons: A new platform for quantum optics" file
156 June 14 (THU), 10:00 AM  E6-2, 2nd fl. #2502  Prof. Kenji Toyoda  Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation file
155 2015/10/15, 10AM  E6-2, 5th fl. #5318  Dr. Mark D. Bird (Florida State University)  Development of Large-Bore, High Field Magnets at the NHMFL
154 2015/10/16, 3PM  E6-2, 5th fl. #5318  Dr. Pierre Pugnat , (CNRS-LNCMI)  High Magnetic Fields to Probe the sub-eV range of Particle/Astroparticle Physics - From the OSQAR experiments at CERN up to new perspectives at LNCMI-Grenoble
153 Dec. 15 (Fri.), 9:20 AM  E6-2, Lecture Room #1323  Prof. Jhinhwan Lee 외 9명  Workshop on Magnetism in Unconventional Superconductors 개최 file
152 April 6, 2016 (Wed), 3:30 PM  E6-2, RM #1323  Dr. Andrei Matlashov (Los Alamos National Laboratory)  Superconducting Quantum Interference Devices for Precision Detection
151 July 21 - August 2  E6-2,# 5318  Junmou Chen/Thomas Flacke/Kaoru Hagiwara/Junichi Kanzaki/Chris Kelso/Jeong Han Kim/Kyoungchul Kong/Gabriel Lee/Hye-Sung Lee/Ian Lewis  Challenges and Opportunities in Theoretical Particle Physics 2019 file
150 December 27(Fri.), 15:00  E6-2,#5318  Han Gyeol Suh  The superconducting order parameter puzzle of Sr2RuO4 file
149 2015/07/15, 2PM  E6-2,1323  Dr. Se Young Park(Rutgers Univ.)  Electronic and optical properties of titanate-based oxide superlattices